Farmed arctic char were divided into two groups after slaughtering. One group (T1) was stored in ice up to 18 d and the other (T2) was stored at 18 ° C for 24 h (temperature increased from 3 ° C up to 12 ° C), then iced and stored up to 18 d . Changes during storage were observed with sensory evaluation using the Quality Index Method (QIM) and Quantitative Descriptive Analysis (QDA), total viable counts (TVC), and hydrogen sulphide (H2S) -producing bacteria. A high correlation between Quality Index (QI) and storage time in ice was found. Storage time could be predicted within ± 1.3 d. The maximum shelf life, determined with QDA and microbial counts, was 17 and 15 d, respectively, for iced (T1) and temperature-abused (T2) arctic char. At the end of shelf life, TVC was 105–106 CFU / g in the flesh of both groups, with H2S producing bacteria constituting a higher proportion of TVC in T2.
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DNA microarrays are currently in use almost exclusively as research tools for gene expression analysis and their application for the identification of organisms is still in its infancy, only documented by a few studies on mammals, bacteria, and viruses. The "Fish & Chips" project aims to demonstrate that DNA chips can be a new innovative tool for the identification of marine animals and phytoplankton. To achieve this goal, fishes, invertebrates, and phytoplankton were sampled in European seas and taxonomically classified. Fragments of their mitochondrial 16S, cyt b, and COI genes and from the nuclear 18S genes were sequenced and served as molecular markers to enable probe design for the microarrays. An on-line data base containing the sequences and all relevant information of the samples has been implemented. A first prototype of a “ Fish Chip „, Is based on more than 400 sequences from the 16S rRNA gene belonging to 46 species. A second microarray prototype serves to identify flatfishes from the North Sea based on COI-and 16S sequences from 70 individuals of 17 fish species. A “ Phytoplankton Chip Is now available with probes for all microalgal classes and many toxic species, as well as a “ Invertebrate Chip „. The results show that this approach is feasible.
A hot water drilling system designed to penetrate to subglacial lakes with a minimum risk of biological contamination has been built and tested. The system uses a heat exchanger to melt snow in a plastic container and the meltwater is pumped through filters and a UV sterilization unit before entering a high pressure pump and heater. The drill hose is made of synthetic rubber and reinforced with high-tensile steel braids. The drill stem is made of stainless steel and is fitted with an exchangeable nozzle. The flow rate of the drilling water at full load is 450 l / hr. The drilling speed set by a winch can be varied between 1.5 mm / s and 1.5 cm / s. In tests of the sterilization efficiency of the system using snow and tap water spiked with bacteria, reduction of cell counts and attenuation of colony forming units to undetectable levels in the drilling water has been achieved. Calculations of heat loss in the drilling hose indicate that the temperature at the drill stem drops from 90 degrees C at the surface to 33 degrees C at 300 m depth; the typical thickness of ice-cover above subglacial lakes in the Vatnajokull ice cap, Iceland. Assuming a drilling speed of 25 m / hr the drill can produce a 300 m deep borehole with a minimum diameter close to 10 cm in 12 hours.
The aim was to develop and evaluate a Quality Index Method (QIM) scheme for fresh cod fillets. Cod fillets were stored at 0–1 ° C on ice up to 14 days. Total viable counts (TVC) and counts of H2S-producing bacteria were done. A QIM scheme for fresh cod fillets to evaluate freshness was proposed. A high correlation between the Quality Index (QI) and storage time on ice was found. The remaining storage time could be estimated with accuracy of ± 1.3 days when the cod fillets were evaluated with QIM. The maximum storage time was estimated 8 days based on Quantitative Descriptive Analysis and H2S-producing bacteria counts.
The effect of hemoglobin from Atlantic cod (Gadus morhua) and Arctic char (Salvelinus alpinus) on formation of volatile compounds in washed cod model system was studied by GC analysis during chilled storage. Pro-oxidative effect of cod hemoglobin compared to char hemoglobin was observed as higher initial levels of hexanal, cis-4-heptenal and 2,4-heptadienal contributing to higher rancid odor sensory scores. This was in agreement with TBARS and changes in color indicating faster initial oxidation catalyzed by cod hemoglobin. The aldehydes appeared to decline towards the end of the storage time in agreement with TBARS; however, levels of 2,4-heptadienal were considerably higher after 4 days of storage in the arctic char hemoglobin catalyzed system.
We report here the complete sequence and fully manually curated annotation of the genome of strain Ch5, a new member of the piezophilic hyperthermophilic species Thermococcus barophilus.